Deep Deposits Research Articles

The Early Aptian Oceanic Anoxic event (OAE-1a) of the uppermost M'Cherga formation of northern Tunisia: Geochemical characterization and inferred petroleum potential

The Early Aptian organic-rich deep marine deposits of the upper Member of the M'Cherga Formation (Valanginian-Aptian) of northern Tunisia were studied based on a multidisciplinary approach including biostratigraphy, sedimentology and organic geochemistry. This study is based on the analysis of 128 samples collected from three sections (Oued Bazina, Djebba and Tel Ghozlene) selected from the salt dome zone (SDZ) and one section of Jebel Oust, situated westward of the Tunisian range. This work is supplemented by previous research undertaken on Oued Zarga and Jebel Ammar sections. Taxonomic analysis of previous and new data (ammonites and planktonic foraminifera) indicate that three informal lithological units rich in organic matter (U1, U2 and U3) are of Early Aptian age, covering both Blowiella blowi and Leupoldina cabri planktonic foraminiferal zones and indiscriminate Lowermost Aptian to the Deshayesites deshayesi – Dufrenoyia furcata ammonite Zones interval.The Rock-Eval analytical results indicate that the studied Early Aptian strata are relatively rich in total organic carbon (TOC) content with values reaching 4.6 % within the U3 (Leupoldina cabri biozone). The latter occurring in the different studied sections constitutes an important deepening phase related to a global sea-level rise testified by the development of well laminated platy limestones containing abundant ammonites and radiolaria. This unit (U3), covering Leupoldina cabri planktonic foraminiferal zone and Deshayesites deshayesi to Dufrenoyia furcata ammonite Zones interval records the Oceanic Anoxic Event -1a (OAE-1a).The palynofacies assemblages show that the organic matter is mainly represented by amorphous particles. The Tmax values ranging from 437 °C to 456 °C (Mean Tmax: 446 °C) and the measured vitrinite reflectance ranging from 0.79 to 1.03 %, indicate that most samples are early mature except for those of the Tel Ghozlene (TG) section which are within the peak oil-generation-window. Lateral facies and thickness variation, in addition to the organic matter distribution throughout the studied domains, strongly suggest the imprint of salt tectonics both on the sedimentological pattern and associated anoxia during the Aptian. Maturation of the organic-rich facies occurred during the Upper Cretaceous-Paleogene compressional phase and associated salt dome remobilization. Source rocks, developed in the Upper Member of the M'Cherga Formation, are attributed to the OAE1a Event and should be considered when reviewing the petroleum potential of conventional and unconventional resources in northern Tunisia.

Multiple isotopes reveal the impact of land use change on nitrate transport and transformation in deep loess deposits

The deep-rooted economic trees decrease water storage but increase nitrate-nitrogen (NO3–N) accumulation in the soil due to the root water uptake and excessive use of fertilizers. Knowing how the NO3 accumulates in the soil and to what extent it can be flushed out or transformed can provide insights on the processes controlling N flux to waterways. We sampled cultivated farmland and orchards with varying ages of apple and peach trees in the loess deposits to > 15 m depth to measure the contents and isotopes of water and NO3 in soils. The novelty of this study is that the water isotopes are used to analyze water and NO3 transport, while the NO3 isotopes are further employed for NO3 source and transformation analysis. The parabolic NO3–N profiles (258–3579 kg N ha−1) were mainly observed within 0–5 m under different land use types. The surface-aggregated NO3 reservoirs under old apple orchard were about six times of farmland due to the overuse of chemical fertilizers, while those of peach orchard were only half of farmland because of less fertilizer inputs and possible root absorption effects. Piston flow resulted in the overall slow water movement and low NO3 flux under different land use types in deep loess deposits. Despite the soil water recharge by precipitation and low surface evaporation, the strong transpiration effects further resulted in no water and NO3 fluxes in the deep layers under old apple orchard. Nitrate reservoirs were mainly contributed by soil organic N (44 % ± 26 %) and ammonium N fertilizer (36 % ± 20 %), but their transformation was dominated by nitrification under old apple orchard and by mineralization in deep layers. The risks of NO3 bombs are temporarily weakened by lower dried soil layers under deep rooted plants; however, with lower water movement rates and limited denitrification potential, NO3 would eventually reach the aquifers in a few hundred years or more. This study provides new insights for clarifying NO3 transport and transformation processes by combing multiple isotopes, and the NO3 bombs would chronically endanger the sustainable development of terrestrial ecosystems and the environment in arid regions.

High spatiotemporal asynchrony between water deficit and nitrate accumulation under apple orchards in deep loess deposits

Understanding the relationship between water and nitrate in soils is critical to agricultural production and aquifer vulnerability assessments, especially in regions with intensive agricultural activities and thick unsaturated zones. Deep soils usually record long-term variations in coupling water and nitrate processes, influenced by multiple environmental factors. As such, this study aims to investigate water and nitrate-nitrogen (NO3–−N) contents and their relationships in soil profiles of 13–23 m deep under farmland and neighboring apple orchards with different ages. Soil properties were considered to explore the individual effect of a single factor or combined effects of multiple factors by wavelet analysis and partial least squares path models. Compared with farmland, apple orchards had large water deficit and NO3–−N accumulation due to root water uptake and synthetic fertilizer inputs, with high spatiotemporal asynchrony in deep unsaturated zones. Specifically, water deficit and NO3–−N accumulation were respectively observed in relatively stable (5–15 m) and active layers (0–5 m, spatial asynchrony), with higher water deficit rates under young apple trees (e.g., 12 and 22 years old) but larger NO3–−N accumulation rates under old apple trees (e.g., 23–32 years old, temporal asynchrony), respectively. Under farmland and orchard, soil texture-organic carbon regulated soil water movement, while soil water-organic carbon affected nitrate transport and transformation processes, which further altered soil pH and electric conductivity conditions in deep vadose zones. The growth of apple trees leads to asynchronous water depletion and fertilizer accumulation in soils, and the > 20 years apple trees are limited by insufficient water despite the excessive fertilizer. The dried soil layers not only reduce potential groundwater recharge, but also prolong the residence time of nitrate bombs in thick unsaturated zones. This study provides essential information for sustainable management of vegetation and water resources, and benefits the complicated hydrological and biogeochemical cycles in thick vadose zones.

Temporal effective stress response of soil elements below the base of an excavation in sensitive clay

Investigations into the temporally evolving stress state below the base of excavations and underground structures are very scarce, in contrast to studies of horizontal earth pressures during the construction stage. Therefore in this work, the measured temporal response in terms of vertical and horizontal effective stresses and displacements below a tunnel slab at the base of an excavation located in a deep sensitive clay deposit is reported. In addition to the measured unloading response over time, the completeness of the site description and complementary measurements enables future benchmarking of numerical models at boundary and element level. Instrument clusters of earth pressure cells and piezometers were installed at three locations in one cross-section. The monitoring data allows the interpretation of effective stress paths and stress ratios, <i>K</i>=σ'<sub>h</sub>/σ'<sub>v</sub>, at soil element level covering the construction and the serviceability stages. The in situ stress ratios enable a unique comparison to prior laboratory studies of <i>K</i> during unloading. The data presented herein on the evolution of <i>K</i> corroborate, although approximately, previous studies at laboratory scale. Furthermore, at system level, the monitoring data reveal the intricate interplay between deformations resulting from excavation and pile driving.

PERSPECTIVES OF SEARCH FOR RAW HYDROCARBON AND SOLID MINERALS DEPOSITS IN THE EASTERN HALF OF PRECASPIAN DEPRESSION (AKSAI – NORTH MAKAT AREA)

The possibility of identifying deep and ultra-deep raw hydrocarbon deposits and also the deposits of solid minerals in eastern part of Precaspian basin within Aksai-Northern Makat section totaling 70,000 sq.km. has been studied on the basis of the analysis of isodata, geological, tectonic, geophysical maps, mineral resources maps, specialized mineragenic studies, as well as new ideas on geodynamic development of Kazakhstan and, most crucial, taking into account theoretical and practical ideas about origin of abiogenic raw hydrocarbon deposits associated with formation of volcanic hydrogen, referring to the deliverables of gravity study and prospecting work, primarily magnetic prospecting. At the same time, a keen attention has been paid to the deep structure and morphology of Precaspian rift, providing significant impact on the deposits` formation. The analysis resulted with identification of, for the first time ever, several highly promising magnetic anomalies where new shallow, medium and deep petroleum and gas deposits may concentrate, including potential deposits of ferrous, non-ferrous, rare, rare earth and radioactive metals. A considerable effort has also been made to the perspectives of search for oil shale and light tight oil which are potential sources for multiple augmentation of the reserves of natural raw hydrocarbons.

The depositional characteristics of turbidity current in Manila Trench: sediment provenance, geochemical elements and organic carbon burial

Turbidity currents play a significant role in sediment transport in deep ocean, profoundly impacting sedimentation in the abyssal sea. This study focused on a 375 cm long sediment core collected from the Manila Trench, revealing a distinctive 15 cm turbidite layer characterized by coarse sediment, an upward fining pattern, and a basal erosion surface. Analysis of rare earth elements and Nd isotope indicates that this turbidite layer originated from Taiwan Island. Initiated in the estuarine shelf region of southwestern Taiwan Island, the turbidity current transported substantial biogenic debris and marine fresh organic carbon into the Manila Trench. Consequently, the turbidite layer exhibited an elevated CaO content and more positive δ13C values. Despite lower TOC content in the turbidite layer due to coarse particle size, the mixture of marine fresh organic matter significantly lowered the carbon age of this layer compared to the strata both below and above it. The rapid sedimentation of the turbidite deposit led to an organic carbon burial flux comparable to the rate at which normal deep-sea sediment buries organic carbon over seven hundred years. Notably, finer sediment overlaying the turbidite layer acted as a cap, enhancing carbon sequestration within the trench. In contrast to nearby core GEO6, which documented over 11 turbidity currents, core S02 recorded only one event. Detailed bathymetric analysis highlights the crucial role of local topography in detecting and preserving turbidity currents. The insights gained from this study would advance our understanding of how turbidity currents shape and influence the deep ocean sedimentation.

Sequential formulation of all‐way coupled finite strain thermoporomechanics for largely deformable gas hydrate deposits

AbstractWe develop a numerically stable sequential formulation of thermoporomechanics for largely deformable gas hydrate deposits, extended from the fixed stress split of infinitesimal transformation. Constitutive equations are based on the total Lagrangian approach for both flow and geomechanics, including dynamic full tensor permeability and thermal conductivity updated from the deformation gradient. For space discretization, we take the cell‐centered finite volume and node‐based finite element method for flow and geomechanics, respectively. Then, we propose a sequential implicit method for all‐way coupled thermoporomechanics, where the nonisothermal multiphase flow problem of gas hydrates is solved implicitly first and then the geomechanics problem is solved implicitly at the next step. During solution of the flow problem, we fix the rate of first Pioal total stress for numerical stability as well as apply porosity correction and entropy correction to account for geomechanical effects. We test numerical examples where flow and geomechanics parameters are based on deep oceanic gas hydrate deposits. When applying depressurization, even though the results between the infinitesimal transformation and finite strain geomechanics are similar in the early stages due to small deformation, we find differences between them in the late times as deformation becomes large. Accordingly, permeability and thermal conductivity tensors become nonisotropic full tensors although they are initially isotropic. We identify numerical stability of the developed sequential method from the test cases that exhibit the highly complex coupled gas hydrate systems with large deformation. Thus, the proposed sequential formulation can be applied in largely deformable gas hydrate systems.

A study of Au-bearing-nanoparticle-enriched plants from the concealed gold deposits and their prospecting significance

This study analyzes Au-bearing nanoparticles in five plant species (Anemone vitifolia, Taraxacum mongolicum, Artemisia argyi, Larix gmelinii, and Equisetum arvense) from the Yangshan gold deposit. Numerous Au-bearing nanoparticles were discovered in the five predominant plants within the ore deposit. It was found that plants differ in terms of their absorption and tolerance of Au-bearing nanoparticles. Among the five dominant plant species, Anemone vitifolia exhibits the highest absorption and accumulation capacity for Au-bearing nanoparticles, making it an Au-bearing-nanoparticle-enriched plants. The Au-bearing-nanoparticle-enriched plants which can super enrich Au-bearing nanoparticles store more abundant and intuitive information about deeply concealed gold ore bodies. Nanoparticles with similar composition and morphology were found in both the root and stem specimens of the Anemone vitifolia. It is shown that the Au-bearing nanoparticles in the stem cells were probably transported from the root. Furthermore, we discuss the relationship between Au-bearing nanoparticles in plants and deep concealed gold deposits and the process whereby Au-bearing nanoparticles migrate from gold orebodies to plants. The Au-bearing nanoparticles can carry information from the concealed gold ore body to the surface medium, and then be absorbed by the roots of Au-bearing-nanoparticle-enriched plants, gaining access to the aboveground parts of the plants. Therefore, this paper advances a new technology for gold deposit exploration using Au-bearing nanoparticles for the enrichment of plants.

Intra-horn insemination in the alpaca Vicugna pacos: Copulatory wounding and deep sperm deposition.

Alpacas (Vicugna pacos) are reported to be the rare mammal in which the penis enters the uterus in mating. To date, however, only circumstantial evidence supports this assertion. Using female alpacas culled for meat, we determined that the alpaca penis penetrates to the very tips of the uterine horns, abrading the tract and breaking fine blood vessels. All female alpacas sacrificed one hour or 24 hours after mating showed conspicuous bleeding in the epithelium of some region of their reproductive tract, including the hymen, cervix and the tips of each uterine horn, but typically not in the vagina. Unmated females showed no evidence of conspicuous bleeding. Histological examination of mated females revealed widespread abrasion of the cervical and endometrial epithelium, injuries absent in unmated females. Within one hour of mating, sperm were already present in the oviduct. The male alpaca's cartilaginous penis tip with a hardened urethral process is likely responsible for the copulatory abrasion. The entire female reproductive tract interacts with the penis, functioning like a vagina. Alpacas are induced ovulators, and wounding may hasten delivery of the seminal ovulation-inducing factor beta-NGF into the female's blood stream. There is no evidence of sexual conflict in copulation in alpaca, and thus wounding may also be one of a variety of mechanisms devised by mammals to induce a beneficial, short-term inflammatory response that stimulates blastocyst implantation, the uterine remodeling associated with placental development, and thus the success of early pregnancy.

Towards the imaging of deep land ore deposits with ERT-IP method – first results from a demonstration survey in Finland

In this study, we conducted a comprehensive geophysical survey near Kuusamo (Finland) to assess the potential of electrical resistivity methods in delineating mineral deposits at depths greater than 1 km. Preliminary investigations, including magnetic and gravity methods as well as drilling, revealed significant anomalous structures in the survey area. We employed multiple electrical and electromagnetic methods at the site, comprising controlled-source electromagnetic (CSEM), magnetotelluric (MT), electrical resistivity tomography (ERT), and induced polarization (IP). To obtain the geophysical data in very large-scale area, we used a total of 25 transmitter dipoles with 1km long using three distinct transmitter systems and recorded data at 119 receiver stations. In this paper, we present the acquisition and preliminary results from ERT-IP. Analysis of the resistivity and IP responses revealed notable IP signals at depths exceeding 1.5 km. Meanwhile, the resistivity data indicated generally very high values, around 10,000 ohm-m, with complex variations observed near the surface.

In silico and in vitro assessment of an optimized QbD-guided myoinositol and metformin-loaded mucus-penetrating particle-based gel for the amelioration of PCOS.

Polycystic ovarian syndrome (PCOS) is a multi-factorial endocrine disorder affecting women of reproductive age. However, its high prevalence and the unsuccessful translation of conventional modalities have made PCOS a pharmaco-therapeutic challenge. In the present study, we explored bi-formulations (comprising metformin-loaded mucus-penetrating nanoparticles, MTF-MPPs, and myoinositol-loaded mucus-penetrating particles, MI-MPPs) incorporated in a carbomer gel tailored for intravaginal administration. For the development and optimization of the MPPs-gel, a QbD (quality by design) approach was employed, including the initial and final risk assessment, central composite design of experts, and method validation. The optimized MTF-MPPs and MI-MPPs possessed an optimum nanometric particle size (195.0 nm and 178.8 nm, respectively) and a PDI of 0.150 and 0.123, respectively, together with a negligible negative zeta potential (-5.19 mV and -6.19 mV, respectively) through the vaginal mucus. It was observed that the MPPs are small and monodisperse with a neutral surface charge. It was observed that the MPPs-gel formulations released approximately 69.86 ± 4.65% of MTF and 67.14 ± 5.74% of MI within 120 h (5 days), which was observed to be sustained unlike MFT-MI-gel with approximately 94.89 ± 4.17% of MTF and 90.91 ± 15% of MI drugs released within 12 h. The confocal microscopy study of rhodamine-loaded MPPs indicated that they possessed a high fluorescence intensity at a depth of 15 μm, while as the penetration trajectory in the vaginal tissue increased to 35 μm, their intensity was reduced, appearing to be more prominent in the blood vessels. The analyzed data of MPPs-gel suggest that the optimized MPPs-gel formulation has potential to reach the targeted area via the uterovaginal mucosa, which has a wide network of blood vessels. Subsequently, in vivo studies were conducted and the results revealed that the proposed MPPs-gel formulation could regulate the estrous cycle of the reproductive system compared to the conventional formulation. Moreover, the formulation significantly reduced the weight of the ovaries compared to the control and conventional vaginal gel. Biochemical estimation showed improved insulin and sex hormone levels. Thus, the obtained data revealed that the deep penetration and deposition of MTF and MI on the targeted area through intravaginal delivery resulted in better therapeutic effects than the conventional vaginal gel. The obtained results confirmed the amelioration of PCOS upon treatment using the prepared MPPs-gel formulation. According to the relevant evaluation studies, it was concluded that MPPs-gel was retained in the vaginal cavity for systemic effects. Also, the sustained and non-irritating therapeutic effect meets the safety aspects. This work serves as a promising strategy for intravaginal drug delivery.

A Medium‐Sized Paleo‐Tsunami Reconstruction by a Deep Neural Network Processing Sedimentary Deposits

AbstractReconstructing the magnitude and recurrence time of tsunamis, one of the most destructive and unpredictable natural hazards impacting coastal communities, is essential. While major tsunamis are the most studied due to their disastrous impact, small/medium tsunamis (SMTs) are much more frequent and can still significantly impact the coast. Therefore, SMTs potentially provide an extensive archive of information preserved in the geological record. Analyzing the deposits of small/medium paleo‐tsunamis (SMPTs) opens a window into when their direct observation was unavailable. However, deposits of SMPTs are often degraded, traditional sediment deposition inversion models might fail. Recent research has shown that Deep Neural Networks (DNN) can effectively reconstruct the flow conditions of major tsunamis from their deposits. We evaluate the effectiveness of this approach in reconstructing the characteristics of a recent medium size tsunami (2006 Java) and of a medium paleo‐tsunami (1929 Grand Banks). We successfully reconstruct the flow characteristics of the 2006 Java event and show that an inversion of comparable quality is possible for the 1929 Grand Banks tsunami, despite greater uncertainties due to the deposit degradation. Our research shows that Machine Learning has the potential to unseal the meaning of data of thousands SMPTs.

Microfacies and Depositional Model of the Shuaiba Formation (Lower Cretaceous), in Selected Wells, Southern Iraq

The Shuaiba Formation (Aptian age) is an important formation due to its wide extent in Iraq and Arabian Gulf. In northern Iraq, it is called Qamchuqa Formation and has an important role in contracting the Arabian plate. The study focused on several wells, which are: ZB-290, WQ1-353, RU-358, R-624, and R-5 from several selected fields, such as Zubair, Rumaila, and West Qurna in southern Iraq. The purpose of the study is to determine the sedimentary and paleontological components of the Shuaiba Formation. The lithology of the Shuaiba Formation consists of very fine crystalline massive limestone that gradually converts to chalky limestone with a large percentage of dolomites, especially in the middle part of the formation. The thickness of the studied formation is about 50 – 110 meters and its main microfacies are two types, which are carbonate and dolomite. The carbonate is subdivided into five secondary types, which are burrowed bioclastic lime mudstone, planktonic foraminiferal lime mudstone, larger foraminifera wackestone, algal wackestone and mixed planktonic, and benthonic Foraminifera wackestone, in addition, to dolostone microfacies. The effect of the diagenesis in the formation is distinguished and most of these processes are destructive, such as dissolution and stylolite. The first depositional stage of the investigated area began with sea level rise following the deposition of the Zubair Formation from still stand. Shuaiba Formation deposited within the ramp setting as the water level rose. During the late Aptian, tectonic and sea levels were the active factors that controlled the deposition of the formation. According to data collected from microfacies and diagenesis processes, the Shuaiba Formation has several depositional environments, which are from the shallowest: restricted, open marine (inner ramp), mid ramp, and finally outer ramp. Generally, toward the upper sequence, the formation reflects deep deposits and then starts to be less deep until it is a shallow basin (Nahr Umr).

Development of methodological solutions for the efficient development of gas condensate deposits in low-permeability reservoirs with complex phase behavior of reservoir fluid

Efficient production of gas and condensate from deep deposits requires the solution of a set of scientific and methodological problems, including the assessment of distribution of the initial fluid composition and properties within the deposit; predicting the complex phase behavior of the reservoir fluid at near-critical conditions and under the influence of the porous medium; modeling the formation of condensate banks in multiphase flows, taking into account velocity effects, variable interfacial tension, non-equilibrium phase transitions and complex well completions; etc. The paper presents the developments of Oil and Gas Research Institute of the Russian Academy of Sciences in this area, with an emphasis on recovery of the unique hydrocarbon reserves of the Achimov deposits of the Urengoy oil and gas condensate field.

Engineering behaviour of in situ cored deep cement mixed marine deposits subjected to undrained and drained shearing

The deep cement mixing (DCM) is used to improve the capacity and reduce the settlement of the soft ground by forming cemented clay columns. The investigation on the mechanical behaviour of the DCM samples is limited to either laboratory-prepared samples or in-situ samples under unconfined compression. In this study, a series of drained and undrained triaxial shearing tests was performed on the in-situ cored DCM samples with high cement content to assess their mechanical behaviours. It is found that the drainage condition affects significantly the stiffness, peak and residual strengths of the DCM samples, which is mainly due to the state of excess pore water pressure at different strain levels, i.e. being positive before the peak deviatoric stress and negative after the peak deviatoric stress, in the undrained tests. The slope of the failure envelope changes obviously with the confining pressures, being steeper at lower stress levels and flatter at higher stress levels. The strength parameters, effective cohesion and friction angle obtained from lower stress levels (c′0 and φ′0) are 400 kPa and 58°, respectively, which are deemed to be true for design in most DCM applications where the in-situ stress levels are normally at lower values of 50–200 kPa. Additionally, the computed tomography (CT) scanning system was adopted to visualize the internal structures of DCM samples. It is found that the clay pockets existing inside the DCM samples due to uneven mixing affect markedly their stress-strain behaviour, which is one of the main reasons for the high variability of the DCM samples.

Peperites

Peperites are volcanosedimentary materials generated by the mingling of magma and unconsolidated wet sediments. They have unique insights into submarine volcanisms and the tectonic environments where they form. For the 1st time, the authors identified two types of peperites (blocky and fluidal) hosted by micritic limestone rocks in the Walash Volcanosedimentary Group of the Mawat area, Kurdistan Region-Iraq. They are designated as peperitic facies one and two (PF1 and PF2) and consist of black basaltic rocks mixed with chocolate-brown micritic limestone rocks. Their abundance demonstrates the contemporaneity of deep marine sediment deposition and submarine volcanism during Walash’s nascent arc. Despite hydrothermal alteration, the basaltic rocks retained their magmatic textures. Basaltic rocks comprise mainly albite, anorthite, diopside, hematite, and alkali-feldspar. Calcite dominates micritic limestone rocks, while quartz is minor. Based on geochemical data, igneous sections are basaltic rocks with tholeiitic series that are strongly enriched in Light Rare Earth Elements with low concentration ratios of (La/Yb) and (Sr/Y), indicating geochemical affinity to normal island arc basalt with a primitive arc signature. Furthermore, their formation is thought to be caused by partial melting of subducted slabs deep within 30 km and the associated derived fluids above the subducted slab. Thirteen species of planktonic foraminifera (Morozovella) are identified through paleontological research and biostratigraphy. Using these various tools lead the authors to illustrate the tectonic setting of the formation of peperitic rocks in arc fronts of the subducted Walash arc during the Middle to Late Paleocene (60 Ma).

Reconstituted dry powder formulations of ZnO-adjuvanted ovalbumin induce equivalent antigen specific antibodies but lower T cell responses than ovalbumin adjuvanted with Alhydrogel® or cationic adjuvant formulation 01 (CAF®01)

Most licensed human vaccines are based on liquid dosage forms but have poor storage stability and require continuous and expensive cold-chain storage. In contrast, the use of solid vaccine dosage forms produced by for example spray drying, extends shelf life and eliminates the need for a cold chain. Zinc oxide (ZnO)-based nanoparticles display immunomodulatory properties, but their adjuvant effect as a dry powder formulation is unknown. Here, we show that reconstituted dry powder formulations of ZnO particles containing the model antigen ovalbumin (OVA) induce antigen-specific CD8+ T-cell and humoral responses. By systematically varying the ratio between ZnO and mannitol during spray drying, we manufactured dry powder formulations of OVA-containing ZnO particles that displayed: (i) a spherical or wrinkled surface morphology, (ii) an aerodynamic diameter and particle size distribution optimal for deep lung deposition, and (iii) aerosolization properties suitable for lung delivery. Reconstituted dry powder formulations of ZnO particles were well-tolerated by Calu-3 lung epithelial cells. Furthermore, almost equivalent OVA-specific serum antibody responses were stimulated by reconstituted ZnO particles, OVA adjuvanted with Alhydrogel®, and OVA adjuvanted with the cationic adjuvant formulation 01 (CAF®01). However, reconstituted dry powder ZnO particles and OVA adjuvanted with Alhydrogel® induced significantly lower OVA-specific CD8+CD44+ T-cell responses in the spleen than OVA adjuvanted with CAF®01. Similarly, reconstituted dry powder ZnO particles activated significantly lower percentages of follicular helper T cells and germinal center B cells in the draining lymph nodes than OVA adjuvanted with CAF®01. Overall, our results show that reconstituted dry powder formulations of ZnO nanoparticles can induce antigen-specific antibodies and can be used in vaccines to enhance antigen-specific humoral immune responses against subunit protein antigens.

Inert Gas—A New Geochemical Technology for Natural Gas Hydrate Exploration in Midlatitude Permafrost

The development of geochemical exploration technologies unaffected by marsh microorganisms is necessary to improve the prediction of wells and explore for natural gas hydrates in mid-latitude permafrost areas. Here, we examine the potential of inert gas as a new tool for the investigation of gas hydrates in permafrost areas. The study area, 150 km2 in size, is situated in the alpine wetland landscape of the Qilian Mountains. The sampling density and depth were 2 points/km2 and 60 cm, respectively. In total, 300 soil and headspace gas samples were collected. The chromatographic backflush technique was used to analyze the inert gases helium (He) and neon (Ne) in the headspace gas samples. A comprehensive interpretation was conducted based on geological and geochemical survey results. We propose a geogas migration mechanism of inert gases in the soil above the natural gas hydrate deposits. The inert gas anomalies near the ground surface of the Muli coalfield in the Qilian Mountains, derived from the deep hydrate deposits and fault structure, are not affected by marsh microorganisms. Thus, inert gas anomalies are practical tools for natural gas hydrate exploration in permafrost areas.

Variable Ophiomorpha ichnofabric: Improving the understanding of mouth bar environments in fan-delta complex depositional settings from the Upper Cretaceous of NW South America

Fan-delta deposits, an important sedimentary component of fan-delta complexes, are scarcely described in the ancient record because it is very difficult to distinguish them from other types of coarse-grained deposits (e.g., alluvial, fluvial, or deep marine deposits). This obstacle is overcome when a well-record of physical/biogenic sedimentary structures or fossils unambiguously marks the influence of the receiving basin. However, this is usually not the case. Here, we present the Ophiomorpha ichnofabric record as a key proxy of marine influence within a generally fluvial-dominated system for improving the paleoenvironmental understanding and reconstructing animal-substrate interplay during the evolution of a fan-delta complex. The ichnological record, together with detailed sedimentological analysis, allows us to define three ichnofabric types, distributed in four levels. The stratigraphic distribution of these features points to distal alluvial environments towards the base, dominated by debris and sheet flows deposits and locally shallow braided channels; they evolve upward into well-developed braided fluvial system whose facies arrangement is related to channel fills, locally influenced by debris flows. Subsequently, a basinward migration of the sedimentary system is recorded through the occurrence of the first level with Ophiomorpha ichnofabric A, and then ichnofabrics A and B in levels 2 and 3, respectively, suggesting marine-influenced mouth bar settings. Toward the top, another steep basinward migration is evidenced by Ophiomorpha ichnofabric C in level 4, indicating wave-dominated processes in distal mouth bars environments. The record of marine-influenced and dominated levels may indicate relative sea-level fluctuations related to local or autogenic processes at the basin scale. Furthermore, the present study demonstrates the ability of Ophiomorpha tracemaker to colonize challenging sedimentary environments.

GAS COMPOSITION AND MICROORGANISMS OF GROUND ICE IN RUSSIAN ARCTIC

Link for citation: Butakov V.I., Slagoda E.A., Zavatsky M.D., Ivanov V.I. Gas composition and microorganisms of ground ice in Russian Arctic. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 9, рр. 63-75. In Rus. Relevance. The increase in the concentration of greenhouse gases in the atmosphere is a fundamental problem on a planetary scale. The source of greenhouse gases in the subsurface horizon of soil can be both deep deposits of hydrocarbons and organic matter processed by microorganisms during the thawing of the ice-rich soil. To determine the source of the gas it is necessary to examine both its quantity and composition and the microorganism content in the subsurface ice. Taking into account the dynamic development of the energy complex in the north of Western Siberia it is necessary to take into account the geotechnical risks associated with the release of greenhouse gases from frozen deposits. Purpose: to study the composition and identify the sources of greenhouse gases in the ice and the ice-rich soil on account of the ice formation conditions and the microorganism content. Objects: ice wedge, hydrogenic and segregational genesis of ice, ice-rich soil of northern Western Siberia and Central Yakutia, collected by expeditions Earth Cryosphere Institute, Tyumen scientific center SB RAS in 2011–2021. Methods of research and interpretation of chemical composition. The structure of frozen deposits has been investigated by cryolitological methods. The monoliths of the ice and the frozen deposits were stored at –18 °C. Gas was extracted from the monoliths with the determination of volume fraction by thermovacuum degassing method. The composition of gases is determined by gas chromatography. Normalization of the gas composition with solubility values in water was carried out. Volume fractions of gas in free and dissolved forms was calculated. The data processing were implemented by means of «Geochem Anomaly» program. Cultivated psychrophilic microorganisms were studied by seeding on nutrient media; the total number of microorganisms was determined by epifluorescent microscopy. Results. The contents of N2 (74,9–87,8 %), O2 (11,7–20,3 %), CO2 (0,01–3,28 %), CH4 (0,003–7, 35 %), H2 (0,001–0,035 %) and hydrocarbons with an atom content from 2 to 6 (2,0×10–5–2,8×10–3 %) are determined in ice and ice-rich soil. The value of N2 and O2 in the gas composition of ice is close to atmospheric air. The ice has wide variations in gas saturation (1,1–21,1 %), CH4 and CO2 content. The freezing of gas-saturated solution occurred for the ice formation, part of the air was in a free form (from 30 to 75 %). Calculated indexes CH4/(C2H6+C3H8) and C2H6/C2H4 indicate biogenic hydrocarbon genesis. The composition of gas bubbles is recalculated for the volume of the entire sample: CH4 content is insignificant in ice wedge, closed-cavity ice and icing (averages 51, 81 and 1 ppmV, respectively). The low amounts of CH4 could be produced by forming these types of ice from the sediments of the active layer, as the dependence of the gas composition on the peat element amount is established. CH4, CO2 and H2 contents increased in samples with peat elements. In interbedding ice the CH4 content is high (216 ppmV). CO2 (up to 3007 ppmV) was accumulated in the texturing ice, and hydrogenic wedge-shaped ice showed high levels of CH4 (up to 4032 ppmV) as the ice was frozen in an enclosed volume. The ice of peat mound has a maximum content of CH4 (15545 ppmV) and high CO2 (2466 ppmV); inclosing sediments flooded with marginal-marine waters are the source of high values of CH4 and CO2. The cultivated psychrophilic microorganisms were identified in the surface ice, and their maximum quantities were identified in segregated formations – up to 1680 KOU/ml, in textural ice – up to 1032 KOU/ml. High concentrations of greenhouse gases are found in frozen peat – CO2 (1075 ppmV), H2 (9 ppmV), CH4 (262 ppmV) and other hydrocarbons due to activity of microorganisms, which results in accumulation of these gases. High gas saturation and CH4 and CO2 levels indicate the formation of gaseous composition by both aerobic and anaerobic microorganisms.